I can agree with the idea that a bad guy should be evil. However, once in a while it's nice to see one who still has a bit of humanity left to him. Ock's drive in the movie was more personal... he just wanted to finish his life's work. His methods become a bit more ruthless, sure. But he's not trying, intentionally, to destroy humanity. It just might happen as a little side accident, if you get my meaning. I'm leaving the ruthless, merciless evil for characters like Green Goblin (both Norman and Harry) who is filled with pure hatred and a desire for revenge. Same with Venom and Carnage. I still think it was nice to see some humanity in Ock, though.
As for other comic adaptations, I loved the graphic novel for Road to Perdition. Very well done. Max Allan Collins did a great job with it.